Device for breaking pavement and the like

ABSTRACT

An impact tool to be mounted upon an implement, for breaking pavements and similar material. It comprises a hammer that is retracted against an &#39;&#39;&#39;&#39;air spring&#39;&#39;&#39;&#39; or similar means by a hydraulic cylinder to store energy in the spring. Means is provided to release the hammer so retracted, and permitting it to make impact with a chisel or point resting on the material to be broken. This tool can be positioned for operation in a horizontal, as well as in a vertical position.

United States Patent John B. Weiss [56] References Cited UNITED STATES PATENTS 779 12/1967 Cunningham................

Primary Examiner-Ernest R. Purser Attorney-Axel H. Johnson [72] inventor 5535 19th Ave., Kenosha, Wis. 53140 [21] AppLNo. 837,694

[22] Filed June30,1969 [45] Patented Jon.5, 1971 [54] DEVICE FOR BREAKING PAVEMENT AND THE ABSTRACT: An impact tool to be mounted upon an implement, for breaking pavements and similar material. It comprises a hammer that is retracted against an air spring or similar means by a hydraulic cylinder to store energy in the spring. Means is provided to release the hammer so retracted, and pennitting it to make impact with a chisel or point resting on the material to be broken. This tool can be positioned for operation in a horizontal, as well as in a vertical position.

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D m m 2 m mm mm m C 5 LI 4U mm H Um U fir t PATENTEU JAN 5 Ian SHEET 1 OF 3 vim 5 INVENTOE JdH/Y 5. 01 5/55 PATENTEDJAN slsm v I 3 552501 snwaura DEVICE FQR BIIEAKING PAVEMENT AND THE LIKE BAGKGROUND OF THE INVENTION I. Field of the Invention This invention relates to devices employed for breaking pavements, stone, concrete walls and similar materials, and to reduce such materials to a size for convenient disposal.

2. Description of the -Prior Art The prior art embrace devices such as are-disclosed in the US. Pat. Nos. listed-below: Otto et al. 2,l07,495 Lutz etal. 2,844,006 McGonigal, 3,369,616. I

The customary device of this nature employs a freelyfalling? hammer which precludes positioning it for operation I in any other position than in the vertical, such as, for example,

when breaking vertical structures such as concrete walls.

9 SUMMARY or THE INVENTION This invention comprises a hammer slidable in a tubular frame which is supported on an implement. A point or chisel is also slidable in the tubular frame and rests in contact with the material to be brokemA- hydraulic cylinder retracts the hammer to store'up energy in a device called an air spring. Means is provided to release the energy so stored up, to cause a the hammer to strike thepoint and fracture the material. The frequency of the operating cycle may be upwardly of 60 strokes per minute. An object,therefor, of this invention is to provide an impact tool that can be employed in a horizontal as well as in the customary vertical position.

alternate position thereof in dotted lines.

FIG. 2 is an elevational front view of the device.

FIG. 3 is an enlarged fragmentary sectional view taken at 3-3 .of FIG. 2', and showing the hammer after the impact stroke, and in position to be retracted in preparation for another stroke of impact.

FIG. 4 is a top view of FIG. 3.

FIG. 5 is a fragmentary sectional view, similar to FIG. 3, but showing the air spring compressed, and at the moment of release of the hammer for its impact with the point.

FIG. 6 is a fragmentary sectional view taken in the direction of 6-6 of FIG. 3, and with parts broken away.

FIG. 7 is a section taken at 7- 7 of FIG. 6.

.FIG. 8 is an enlarged view of a portio'nof FIG. 5.

FIG. 9 is a fron'tview of FIG. .8.

FIG. 10 is a'projected view of FIG. 8.

FIG. 11 is a section taken at 11-1 I of FIG. I.

FIG. I2 is a fragmentary view of the device with the hammer released for the impact stroke.

The preferred form of the device is shown in FIGS. I and 2,

and comprises a frame having a longitudinal tubular member brackets 14 and I6 are secured rearwardly to member 12 as by welding, and provide the means to support the device on an implement. The customary means'provided on the usual implement to engage the brackets 14. and 16, are the piston rod I I8 and the arm 20, respectively.

A pair of spaced walls 22 and 24 are welded, in this in- I stance, to tubular member 12, and define an enclosure, as

rubber which is inflatable by means of a tire valve 40, and has a pair of annular convolutions 42 which when compressed, appear as in FIG. 5. When expanded, as when released for impact, the convolutions appear as in FIGS. 1, 3 and 6. Metal end plates 44 and 46 are secured integrally with the resilient portions of the air spring" 38. Cap screws 48 secure the plate 44 to member 34. A locating plate 50 is secured to end plate 46 by similar means to that employed with respect to member 44. Plate 50 is keyed against lateral displacement relative to cap 30 by means of keys 52 and 54. Keys 52 are secured to cap 30 as .by welding, and embrace plate 50. Keys 54 are likewise secured to plate 50 and engage notches in the edges of hammer 28.

A resilient bumper 56 is supported on tubular member 12 by means of a bracket 58. The purpose of bumper 56 is to limit the lowest position of cap 30 when the tool is raised for transport. This position of cap 30 is shown by dotted lines in FIG. I.

A point or chisel 60 is slidable in tubular member 12 coextensively with hammer 28. Stops 62 are secured to point 60 and abut the end of tubular member 12 when chisel 60 rests upon the material to be fractured, thereby limiting the upward position of the chisel. A longitudinal slot 64 is provided in .chisel 60. A bolt 66 is passed through member 12 and slot 64 to retain the chisel in the tubular member, and to permit limited travel of the chisel to the length of the slot, when the tool is out of contact with the material to be fractured.

A hydraulic cylinder 68 is positioned between walls 22 and 24, and is pivoted on a pin 70 which is suitably supported by "walls 22 and 24. Cylinder 68 is directed axially and convergently toward hammer 28 at an angle a, and downwardly from the pin 70, and has a ram 72. Cylinder 68 operates in two member 12 to expose the front face of hammer 28, as shown I2 of a rectangular cross section. Longitudinally-spaced in FIGS. 3 and 6.

A cam block 92 is secured to hammer 28 within opening 90 by suitable screws. Cage 82 receives cam block 92 therein, and permits roller 84 to engage the surface of hammer 28 as shown in FIG. 3. Cam block 92 has a face 94 normal to the surface of Hammer 28 and which face terminates in a bead 96. The purpose of bead 96 is to delay the release of hammer 28 and eliminate unnecessary sensitivity. Cam block 92 has a land surface 98 uponwhich roller 84 rides during periods when the ram 72 is advancing to repeat an impact stroke, and when the tool is suspended freely, and the hammer 28 and point or chisel 60 assume an extended position. In the extended position cam 92 is in the extreme lower position, and actuation of the controls would limit roller 84 to travel between the position shown in FIG. 12 by solid lines and that shown by dotted lines. This arrangement provides what is known as a dead-man control, and prevents unintentional actuation of the hammer 28.

The hydraulic circuit is shown in FIG. 1, diagrammatically and comprises a reservoir 100, a pump 102, and operator-controlled valve 104; all of which are part of the equipment of the implement on which the tool is mounted. A continuous reciprocating valve 106 is addedto provide operation of the ram 72 at strokes up to 150 per minute; the usual number of terminates upwardly in a cap 30. The lower end of hammer 28 strokes being about 60 to per minute.

A stop 108 is secured to cylinder 68 and is provided with a rubber face which contacts the surface of tubular member 12 when the cylinder 68 is in the position shown in FIGS. 5 and 12.

A spring 110 partially surrounds cylinder 68 and the ends of the spring are anchored in walls 22 and 24 by bolts such as 112. Spring I10 assures that roller 84 will be constantly urged toward hammer 28 or cam block 92.

A bumper pad 114 is positioned as shown in FIG. 3, being secured between walls 22 and 24. The resilient portion of pad 114 is bolted to a plate 116 by suitable bolts. The purpose of pad 114 is to provide a bumper for cage 82 when the latter is suddenly released from cam block 92 at the time of impact.

A cover 118 closes the opening between walls 22 and 24 to prevent damage to the elements enclosed therebetween. Bolts or preferably pins 119 extend through cover 118 and walls 22 and 24. Cotter pins secure the pins against accidental removal. A handle 120 is provided for convenience in removing or replacing the cover.

A lifting ring 122 is welded to support member 34 to provide a means to conveniently handle the tool when mounting it or preparing it for transport.

When preparing this impact tool for operation, an initial pressure of approximately to 40 pounds of air is supplied to the air spring 38 by means of the valve 40. The point or chisel 60 is then pressed upon the surface to be broken, as shown in FIG. 1. Valve 104 is then actuated manually by the operator to retract hammer 28. As ram 72 is being retracted, roller 84 moves outwardly normal to the face of hammer 28 and along face 94 of cam block 92. As the retraction continues, air spring 38 is being compressed. Roller 84 finally reaches bead 96 and is forced over the bead by reason of stop 108 in its engagement with the wall of tubular member 12 as shown in FIG. 5, thus suddenly releasing hammer 28 to make impact with point 60 in response to the energy stored in air spring 38. The valve 106, owing to its continuous and repeating operation, will then extend ram 72 to again assume the position shown in H0. 3, in preparation for another cycle. The cycle will then be automatically repeated and will continue to do so during the time the operator maintains the valve 104 in the operating position.

A novel feature of this invention is the positioning of cylinder 68 on an axis converging downwardly relative to the axis of hammer 28. This relationship results in transporting roller 84 along face 94 of cam block 92 during the retracting of ram 72, compelled by engagement of stop 108 with the wall of tubular member 12, until roller 84 passes over bead 96 and is released from cam 92.

Other objects and advantages of this invention will become apparent from a consideration of the detailed description taken in connection with the accompanying drawings wherein an embodiment ofthe invention is shown. It is, however, to be understood that the invention is not limited to the details disclosed, but includes all such variations as fall within the spirit of the invention: For example, it is within the purview of the invention to make the hammer 28 of other cross sections as a substitution for the rectangular shape. Also it is intended that the brackets 14 and 16 may be otherwise positioned if so dictated by convenience.

The above being a complete description of an illustrative embodiment of the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

lclaim: i

1. A device for breaking pavement material and the like, comprising, in combination a framehaving an upright portion comprising a tubular passageway defin'ed'by a front wall, said wall having an opening therein, a hammer. having an upper and a lowerend, and slidable in said passageway, a point slidable in said passageway and engaged by said lower end of said hammer, means to limit the travel of said point in said passageway, spaced upright members secured to said frame, a support member secured to said frame and normal to said passageway and spaced upwardly from said upper end, an impact energy-producing means intermediate said upper endand said support member, a hydraulic cylinder intermediate said spaced upright members, and having fluid-connections, a pivot means in said members and normal thereto, for the upper end of said cylinder and spaced forwardly from said front wall, means to urge said cylinder pivotally toward said front wall, a cam block secured to said hammer and positioned in said openin and having a downwardlydirected face extending forwar ly relative with respect to said hammer, said cylinder having a ram, the axis of which is directed convergently downward toward said hammer, said ram terminating in a roller cage embracing said cam block, a cam roller positioned in said cage to engage said lower face adjacent said hammer when said ram is extended downwardly, means associated with said cylinder and said front wall to effect translation of said roller forwardly along said lower face during retraction of said ram into said cylinder thereby raising said hammer and storing energy in said energy-producing means, continued retraction of said ram resulting in disengagement of said roller from said cam block, permitting release of said energy-producing means to expend said energy and force said hammer into engagement with said point, and a hydraulic system connected to said fluid connections.

2. A device as set forth in claim 1, in which said downwardly-directed face of said cam block terminates forwardly in a raised bead portion directed parallel to the axis of said roller.

3. A device as set forth in claim 1, in which said passageway is of a rectangular cross section.

4. A device as set forth in claim 1, in which said impact energy-producing means comprises a pneumatic spring. 

1. A device for breaking pavement material and the like, comprising, in combination a frame having an upright portion comprising a tubular passageway defined by a front wall, said wall having an opening therein, a hammer having an upper and a lower end, and slidable in said passageway, a point slidable in said passageway and engaged by said lower end of said hammer, means to limit the travel of said point in said passageway, spaced upright members secured to said frame, a support member secured to said frame and normal to said passageway and spaced upwardly from said upper end, an impact energy-producing means intermediate said upper end and said support member, a hydraulic cylinder intermediate said spaced upright members, and having fluid connections, a pivot means in said members and normal thereto, for the upper end of said cylinder and spaced forwardly from said front wall, means to urge said cylinder pivotally toward said front wall, a cam block secured to said hammer and positioned in said opening and having a downwardly-directed face extending forwardly relative with respect to said hammer, said cylinder having a ram, the axis of which is directed convergently downward toward said hammer, said ram terminating in a roller cage embracing said cam block, a cam roller positioned in said cage to engage said lower face adjacent said hammer when said ram is extended downwardly, means associated with said cylinder and said front wall to effect translation of said roller forwardly along said lower face during retraction of said ram into said cylinder thereby raising said hammer and storing energy in said energy-producing means, continued retraction of said ram resulting in disengagement of said roller from said cam block, permitting release of said energy-producing means to expend said energy and force said hammer into engagement with said point, and a hydraulic system connected to said fluid connections.
 2. A device as set forth in claim 1, in which said downwardly-directed face of said cam block terminates forwardly in a raised bead portion directed parallel to the axis of said roller.
 3. A device as set forth in claim 1, in which said passageway is of a rectangular cross section.
 4. A device as set forth in claim 1, in which said impact energy-producing means comprises a pneumatic spring. 